Non contact type IC card

ABSTRACT

A memory ( 1 ) in a non contact type IC card ( 100 ) includes a data protection region (B 2 ) storing data requiring security and an region (B 1 ) storing other data. A main control circuit ( 2 ) generates data to be stored and designates a location for data storage in the region (B 1 ) or the data protection region (B 2 ) according to a content of the data. An address non selecting circuit ( 4 ) selects whether the generated data is to be written into the location in the data protection region (B 2 ) designated by the main control circuit ( 2 ) according to a state of a state setting circuit ( 3 ).

TECHNICAL FIELD

[0001] The present invention relates to a non contact type IC card, andmore particularly to a non contact type IC card allowing the protectionof data stored in the card and the prevention of data falsification.

BACKGROUND ART

[0002] A non contact type IC card performing data communication with aninterrogator installed outside has been used conventionally. Theexamples include a ticket for ski lift, a seasonal ticket for thetransportation and a prepaid card.

[0003]FIG. 7 is a block diagram schematically showing a basic structureof a conventional non contact type IC card 900. Conventional non contacttype IC card 900 shown herein, which is an IC card performing datacommunication in a signal superposing manner, supplies power andtransmits/receives information using a signal(s) having one or morefrequencies received from the interrogator not shown.

[0004] Conventional non contact type IC card 900 as shown in FIG. 7 isan example of non contact type IC cards utilizing a single frequency andincludes a tuning circuit 20, a rectifying circuit 21, anamplifying/demodulating circuit 22, a modulating/amplifying circuit 23and an SP/PS conversion circuit 24.

[0005] Tuning circuit 20 includes a coil L functioning as an antenna anda capacitor C0. Rectifying circuit 21 rectifies a signal received attuning circuit 20, thereby generates and supplies the power to each partof non contact type IC card 900.

[0006] Amplifying/demodulating circuit 22 amplifies and demodulates dataQ from an interrogator received at tuning circuit 20. A signal outputfrom amplifying/demodulating circuit 22 is SP-converted by SP/PSconversion circuit 24 and then is output to a main control circuit 2described below.

[0007] With reference to FIG. 7, conventional non contact type IC card900 further includes main control circuit 2 and a memory 1.

[0008] Main control circuit 2 processes a signal output from SP/PSconversion circuit 24. Main control circuit 2 generates data DA to bestored in memory 1 described below and designates a location (address)of memory 1 to which data DA is to be written.

[0009] Memory 1 includes normal data storage region B1 and dataprotection region B2. Memory 1 receives data DA via a data line L2 aswell as an address signal AD via an address line L1 indicating anaddress (a location to which data is to be written) to which data DA isto be written. Here, data stored in data protection region B2particularly requires security in order to guarantee a normal datacommunication and whose rewriting is inhibited. An example of such datais an ID number of an ID card holding the personal information.

[0010] In addition, main control circuit 2 reads data from designatedregion B1 or data protection region B2 of memory 1 according to thecontents of data Q received from the interrogator and generates aresponse data A based on the read data. Response data A is PS-convertedat SP/PS conversion circuit 24, processed at modulating/amplifyingcircuit 23 and then transmitted to the interrogator via coil L formingthe antenna.

[0011] In conventional non contact type IC card 900, however, therewriting (falsification) of stored data in memory 1 can be easilyperformed from a device other than the interrogator once the protocol ofthe data communication with the interrogator is decoded, therefore thesecurity cannot be guaranteed.

[0012] Hence an object of the present invention is to provide a noncontact type IC card allowing the prevention of rewriting of a storageregion in which data requiring security is stored.

[0013] Another object of the present invention is to provide a highlyreliable non contact type IC card through the control of rewriting ofthe storage region in which data requiring security is stored.

DISCLOSURE OF THE INVENTION

[0014] A non contact type IC card according to the present invention isresponsive to externally applied data for performing data communication,and includes: a first storing circuit storing data requiring security; asecond storing circuit storing data other than the data to be stored inthe first storing circuit; a control circuit controlling for writing thedata into a location in one of the first storing circuit and the secondstoring circuit according to a content of the data; a selection circuitselecting whether the data is to be written into the location in thefirst storing circuit designated by the control circuit; and a statesetting circuit controlling the selection by the selection circuit, thedata is written into the location in the first storing circuitdesignated by the control circuit when the state setting circuit is in afirst state, whereas, the data is inhibited from being written into thefirst storing circuit designated by the control circuit when the statesetting circuit is in a second state other than the first state.

[0015] In another aspect of the present invention, a non contact type ICcard is responsive to externally applied data for performing datacommunication, and includes: a first storing circuit storing the datarequiring security; a second storing circuit storing data other than thedata to be stored in the first storing circuit; a control circuitcontrolling for writing the data into a location in one of the firststoring circuit and the second storing circuit according to a content ofthe data; a detection circuit receiving a control signal from thecontrol circuit and giving instruction for controlling a state of thefirst storing circuit; and a selection circuit receiving the instructionof the detection circuit and selecting whether the data is to be writteninto the location of the first storing circuit designated by the controlcircuit; and the control signal output from the control circuitindicates whether the first storing circuit is in a data rewritingpermitted state or a data rewriting inhibited state; and the data iswritten into the location in the first storing circuit designated by thecontrol circuit when the detection circuit detects that the firststoring circuit is in the data rewriting permitted state, whereas thedata is not written into the location in the first storing circuitdesignated by the control circuit when the detection circuit detectsthat the first storing circuit is in the data rewriting inhibited state.

[0016] In still another aspect of the present invention, a non contacttype IC card performs a data communication based on an externallyapplied radio wave signal, and includes: a receiving circuit receivingthe radio wave signal; a first storing circuit storing the datarequiring security; a second storing circuit storing data other than thedata to be stored in the first storing circuit; a control circuitgenerating the data based on the radio wave signal received at thereceiving circuit and controlling for writing the data into a locationin one of the first storing circuit and the second storing circuitaccording to a content of the generated data; a detection circuitdetecting a frequency of the radio wave signal received by the receivingcircuit; and a selection circuit selecting whether the data is to bewritten into the location in the first storing circuit designated by thecontrol circuit based on a result of the detection by the detectioncircuit; and wherein the data is written into the location in the firststoring circuit designated by the control circuit, when the receivingcircuit receives the radio wave signal and the frequency of the radiowave signal is detected to be a first frequency by the detectioncircuit, whereas the data is not written into the location in the firststoring circuit designated by the control circuit when the frequency ofthe radio wave signal is detected to be a second frequency other thanthe first frequency by the detection circuit.

[0017] In still another aspect of the present invention, a non contacttype IC card is responsive to externally applied data for performingdata communication, and includes: a first storing circuit storing thedata requiring security; a second storing circuit storing data otherthan the data to be stored in the first storing circuit; a controlcircuit controlling for writing the data into a location in one of thefirst storing circuit and the second storing circuit according to acontent of the data; and a data fixing circuit receiving the data to bewritten into the location in the first storing circuit designated by thecontrol circuit and supplying a particular data; and wherein a value ofthe predetermined data supplied from the data fixing circuit is a valuedetermined by an initial state of the first storing circuit, and whereinonly the particular data supplied from the data fixing circuit iswritten into the location in the first storing circuit designated by thecontrol circuit.

[0018] In still another aspect of the present invention, a non contacttype IC card is responsive to externally applied data for performingdata communication, and includes: a first storing circuit storing saiddata requiring security; a second storing circuit storing data otherthan the data to be stored in the first storing circuit; a controlcircuit controlling for writing the data into a location in one of thefirst storing circuit and the second storing circuit according to acontent of the data; a selection circuit selecting whether the data isto be written into the location in the first storing circuit designatedby the control circuit; and a state setting circuit controlling theselection by the selection circuit; and wherein the data is written intothe location in the first storing circuit designated by the controlcircuit when the state setting circuit is in a first state, whereas, thedata is written into a location other than the location in the firststoring circuit designated by the control circuit when the state settingcircuit is in a second state other than the first state.

[0019] In still another aspect of the present invention, a non contacttype IC card is responsive to externally applied data for performingdata communication, and includes: a first storing circuit storing thedata requiring security; a second storing circuit storing data otherthan the data to be stored in the first storing circuit; and a controlcircuit controlling for writing the data into a location in one of thefirst storing circuit and the second storing circuit according to acontent of the data; and wherein the first storing circuit allowsrewriting of a predetermined times.

[0020] Therefore a main advantage of the present invention lies in theprevention of falsification of storage contents through the control ofrewriting of data stored in a storage portion storing data requiringsecurity.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021]FIG. 1 shows a structure of a main portion of a non contact typeIC card 100 according to a first embodiment of the present invention.

[0022]FIG. 2 shows a structure of a main portion of a non contact typeIC card 200 according to a second embodiment of the present invention.

[0023]FIG. 3 shows a structure of a main portion of a non contact typeIC card 300 according to a third embodiment of the present invention.

[0024]FIG. 4 shows a structure of a main portion of a non contact typeIC card 400 according to a fourth embodiment of the present invention.

[0025]FIG. 5 shows a structure of a main portion of a non contact typeIC card 500 according to a fifth embodiment of the present invention.

[0026]FIG. 6 shows a structure of a main portion of a non contact typeIC card 600 according to a sixth embodiment of the present invention.

[0027]FIG. 7 is a diagram schematically showing a structure of aconventional non contact type IC card 900.

BEST MODES FOR CARRYING OUT THE INVENTION

[0028] First Embodiment

[0029] The first embodiment of the present invention allows theprevention of rewriting of data previously stored in a data protectionregion by controlling an address to which data is to be written, at datawriting for the data protection region of a memory in a non contact typeIC card.

[0030]FIG. 1 shows a structure of a main portion of a non contact typeIC card 100 according to the first embodiment of the present invention.Components similar to those in conventional non contact type IC card 900shown in FIG. 7 are denoted by the same reference numbers and samereference characters and the description thereof will not be repeated.Here, data transmission of the non contact type IC card adopting thepresent invention may be either in a signal superposing method or in asignal separating method.

[0031] Non contact type IC card 100 shown in FIG. 1 differs fromconventional non contact type IC card 900 in that card 100 includes astate setting circuit 3 and an address non selecting circuit 4controlling a write address designated at data writing for dataprotection region B2 of memory 1.

[0032] With reference to FIG. 1, the structure of non contact type ICcard 100 according to the first embodiment of the present invention willbe described.

[0033] Address non selecting circuit 4 receives a write enable signal REsupplied from main control circuit 2 and an address signal AD from anaddress line L1 as inputs. Here, address signal AD designates a locationin data protection region B2 to which data DT on a data line L2 is to bewritten, and write enable signal RE designates a data writing operationto data protection region B2. Address non selecting circuit 4 beingcontrolled by state setting circuit 3 described below outputs an addressselecting signal AC according to address signal AD.

[0034] State setting circuit 3 controls address non selecting circuit 4described above.

[0035] Address selecting signal AC output from address non selectingcircuit 4 changes its state based on a state (active state/inactivestate) of state setting circuit 3. Specifically, when state settingcircuit 3 is in an active state, an output address selecting signal ACselects a location designated by address AD as a location to which datais to be written, whereas when state setting circuit 3 is in an inactivestate, an output address selecting signal AC inhibits the writing to thelocation designated by address signal AD (non select state).

[0036] Data DT will be written into a location in data protection regionB2 corresponding to and based on address selecting signal AC output fromaddress non selecting circuit 4.

[0037] Next, an operation of non contact type IC card 100 according tothe first embodiment of the present invention will be described.

[0038] First, when state setting circuit 3 is in an active state,address non selecting circuit 4 having received write enable signal REand address signal AD outputs address selecting signal AC selecting alocation designated by the address signal AD. In this case data DT willbe written into the corresponding location in data protection region B2.

[0039] On the other hand, when stage setting circuit 3 is in an inactivestate, address non selecting circuit 4 having received write enablesignal RE and address signal AD outputs address selecting signal ACturning the location designated by the address signal AD to a non selectstate. In this case data DT is not written into data protection regionB2.

[0040] One example of such state setting circuit 3 uses a fuse. Forexample, when a fuse is used, any numbers of data can be written intodata protection region B2 before the fuse blow, however, after the fuseblow, data in data protection region B2 can not be rewritten. Themethods of blowing the fuse includes high voltage application, lasercutting, induction heating or the like.

[0041] In other words, by controlling the state of state setting circuit3, non contact type IC card 100 can inhibit the access to dataprotection region B2 for data rewriting after the data requiringsecurity is stored in data protection region B2 (for simplicity thisstate is referred to as protection data storage state).

[0042] Thus in non contact type IC card 100, as the address selectionfor the data protection region can be controlled at the data writingoperation, the falsification of data previously stored in the dataprotection region can be prevented.

[0043] Second Embodiment

[0044] Similar to the first embodiment of the present invention, the noncontact type IC card according to the second embodiment of the presentinvention allows the prevention of rewriting of data stored in the dataprotection region by controlling an address to which the data is to bewritten at the time of data writing to the data protection region in thememory.

[0045]FIG. 2 shows a structure of a main portion of a non contact typeIC card 200 according to the second embodiment of the present inventionand components similar to those in non contact type IC card 100 shown inFIG. 1 are denoted by the same reference numbers and same referencecharacters and the description thereof will not be repeated.

[0046] Non contact type IC card 200 shown in FIG. 2 is different fromconventional non contact type IC card 900 in that it includes a commanddetection circuit 5 and an address non selecting circuit 6 controlling adesignated address to which data is to be written at the time of datawriting to the data protection region of the memory, and controls thesecircuits by a command output from a main control circuit 12.

[0047] With reference to FIG. 2, the structure of non contact type ICcard 200 according to the second embodiment of the present inventionwill now be described.

[0048] Address non selecting circuit 6 receives an address signal AD viaan address line L1 as an input. Here, address signal AD indicates alocation in data protection region B2 to which data DT on a data line L2is to be written. Address non selecting circuit 6 controlled by commanddetection circuit 5 described below outputs address selecting signal ACaccording to the address signal AD.

[0049] Command detection circuit 5 receives an address control commandCOM output from main control circuit 12 and controls address nonselecting circuit 6. Here, address control command COM is a commandpermitting or inhibiting a data writing operation to data protectionregion B2 based on the address signal AD.

[0050] Address selecting signal AC output from address non selectingcircuit 6 changes its state according to a state of command detectioncircuit 5. Specifically, when command detection circuit 5 detects awriting permitted state of a data protection region B2, an addressselecting signal AC selecting a location designated by address AD as alocation to which data is to be written is output. On the other hand, ifdata protection region B2 is detected to be in a writing inhibitedstate, address selecting signal AC turning a location designated byaddress signal AD to a non select state is output.

[0051] Based on the address selecting signal AC supplied from addressnon selecting circuit 6, data DT is written into a correspondinglocation in data protection region B2.

[0052] Next an operation of non contact type IC card 200 according tothe second embodiment of the present invention will be described.

[0053] When an address control command COM permitting the data writingis supplied from main control circuit 12, and is detected by commanddetection circuit 5, address non selecting circuit 6 outputs an addressselecting signal AC selecting a location designated by the addresssignal AD. In this case data DT is written into a corresponding locationin data protection region B2.

[0054] On the other hand, when an address control command COM inhibitingthe data writing is supplied from main control circuit 12, and isdetected by command detection circuit 5, address non selecting circuit 6outputs an address selecting signal AC turning the location designatedby the address signal AD to a non select state. In this case data DT isnot written into data protection region B2.

[0055] Thus, non contact type IC card 200 allows the adjustment ofstorage of data requiring security in data protection region B2 (turningdata protection region B2 to the protection data storage state) andinhibiting the access to data protection region B2 for the datarewriting, through the control of command detection circuit 5 based on acommand output from main control circuit 12.

[0056] As non contact type IC card 200 allows the control of selectionof address of the data protection region at the data writing operation,the falsification of data previously stored in the data protectionregion can be prevented.

[0057] Third Embodiment

[0058] The third embodiment of the present invention allows theprevention of rewriting of data once stored in the data protectionregion in the non contact type IC card through the access control forthe data protection region according to the frequency for datacommunication.

[0059]FIG. 3 shows a structure of a main portion of a non contact typeIC card 300 according to the third embodiment of the present invention,wherein components similar to those in non contact type IC card 100shown in FIG. 1 are denoted by the same reference numbers and samereference characters, and the description thereof will not be repeated.

[0060] Non contact type IC card 300 shown in FIG. 3 is different fromconventional non contact type IC card 900 in that it includes afrequency detection circuit 7 and an address non selecting circuit 8.

[0061] With reference to FIG. 3, the structure of non contact type ICcard 300 according to the third embodiment of the present invention willnow be described.

[0062] Frequency detection circuit 7 detects a frequency of a radio wavereceived by tuning circuit 20 and includes a band pass filter and aswitching circuit inside not shown. When a carrier frequency of areceived radio wave is a predetermined frequency F1, frequency detectioncircuit 7 detects the reception of an intended radio wave.

[0063] Address non selecting circuit 8 receives address signal AD viaaddress line L1 and a write enable signal RE from main control circuit 2as inputs. Here, address signal AD designates a location in dataprotection region B2 to which data DT on data line L2 is to be written.

[0064] Address non selecting circuit 8 controlled by frequency detectioncircuit 7 outputs address selecting signal AC according to addresssignal AD. More specifically, when frequency detection circuit 7 detectsthe reception of an intended radio wave (with predetermined frequencyF1), an address selecting signal AC selecting a location designated byaddress signal AD as a location to which data is to be written isoutput, and otherwise (when received radio wave has a frequency otherthan the predetermined frequency F1), an address selecting signal ACturning the location designated by the address signal AD to a non selectstate is output.

[0065] Based on the address selecting signal AC, data DT is written intothe corresponding location in data protection region B2.

[0066] With reference to FIG. 3, an operation of non contact type ICcard 300 will be described specifically.

[0067] As described above, when a radio wave with a carrier frequency F1is received, address non selecting circuit 8 outputs an addressselecting signal AC selecting a location designated by address signalAD. In this case data DT is written into the corresponding location indata protection region B2.

[0068] On the other hand, when a radio wave with a carrier frequencybeing an original frequency F0 different from F1 is received, addressnon selecting circuit 8 outputs an address selecting signal AC turningthe location designated by address signal AD to a non select state. Inthis case data DT is not written into data protection region B2.

[0069] In other words, non contact type IC card 300 allows theadjustment of the storage of data requiring security in data protectionregion B2 (turning data protection region B2 to the protection datastorage state) and inhibiting the access to data protection region B2for the data rewriting, through the use of different frequencies.

[0070] Thus, as a non contact type IC card 300 allows the access controlfor the data protection region according to the frequency of radio wavefor the data communication, the falsification of data previously storedin the data protection region can be prevented.

[0071] Fourth Embodiment

[0072] The fourth embodiment of the present invention allows theprevention of data falsification, which is the object of the presentinvention, in the non contact type IC card by controlling the data to bewritten at the data writing to the data protection region in the memory.

[0073]FIG. 4 shows a structure of a main portion of a non contact typeIC card 400 according to the fourth embodiment of the present invention,wherein components similar to those in non contact type IC card 100shown in FIG. 1 are denoted by the same reference numbers and samereference characters, and the description thereof will not be repeated.

[0074] Non contact type IC card 400 shown in FIG. 4 is different fromconventional non contact type IC card 900 in that it includes an inputdata fixing circuit 9 controlling data to be written into dataprotection region B2 of memory 1.

[0075] With reference to FIG. 4, the structure of non contact type ICcard 400 according to the fourth embodiment of the present inventionwill be described.

[0076] Input data fixing circuit 9 fixes a state of each location indata protection region B2 of memory 1.

[0077] Input data fixing circuit 9 receives data DT1 via a data line L2as an input, converts data DT1 and outputs data DT2. Data DT2 is data tobe written into data protection region B2.

[0078] A value of data DT2 output from input data fixing circuit 9 isdetermined based on an initial state of data protection region B2. Whenstates of all bits in data protection region B2 are “1”, for example,data DT2 always takes a value of the reverse polarity, in this case “0”.Hence, when main control circuit 2 outputs data DT1 corresponding to thevalue “1”, the data writing to data protection region B2 will not beperformed.

[0079] With reference to FIG. 4, an operation of non contact type ICcard 400 will be described specifically.

[0080] Assume that an initial state of each bit in data protectionregion B2 in memory 1 is set to “1” (the state of bit to “1111”). Inthis case, input data fixing circuit 9 receiving data DT1 outputs onlythe data DT2 of “0” for each bit.

[0081] First, data requiring security will be written into dataprotection region B2 (protection data storage state). Here, assume thatthe protection data storage state is “1100”. As described above, dataDT2 output from input data fixing circuit 9 takes the value “0”.Therefore, the bit once takes the state “0” cannot be returned to thestate “1”. As a result, thereafter, the state of data protection regionB2 (“1100”) cannot be rewritten to “1101”, for example.

[0082] Thus, data protection region B2 of non contact type IC card 400functions as an OTP ROM (a non volatile memory allowing only onerewriting) and once data is stored in the data protection region, trialof the data rewriting is highly likely to result in a failure of anintended data setting.

[0083] Thus, as described above, as non contact type IC card 400 allowsthe control of data to be written into the data protection region at thedata writing operation, the rewriting of data once stored in the dataprotection region can be prevented.

[0084] Fifth Embodiment

[0085] The fifth embodiment of the present invention allows theprevention of data falsification, which is the object of the presentinvention, in the non contact type IC card, by controlling an address towhich data is to be written at the data writing operation to the dataprotection region of the memory.

[0086]FIG. 5 shows a structure of a main portion of a non contact typeIC card 500 according to the fifth embodiment of the present invention,wherein components similar to those in non contact type IC card 100shown in FIG. 1 are denoted by the same reference numbers and samereference characters, and the description thereof will not be repeated.

[0087] Non contact type IC card 500 shown in FIG. 5, is different fromconventional non contact type IC card 900 in that it includes a statesetting circuit 10 and an address non selecting circuit 11 controlling adesignated address to which data is to be written at the writing to dataprotection region B2 of memory 1.

[0088] With reference to FIG. 5, the structure of non contact type ICcard 500 according to the fifth embodiment of the present invention willbe described.

[0089] Address non selecting circuit 11 receives a write enable signalRE output from main control circuit 2 and address signal AD via addressline L1 as inputs. Here, address signal AD designates a location in dataprotection region B2 to which data DT on data line L2 is to be written.Address non selecting circuit 11 controlled by state setting circuit 10described below, outputs address selecting signal AC according toaddress signal AD.

[0090] State setting circuit 10 controls address non selecting circuit11 described above.

[0091] Address selecting signal AC output from address non selectingcircuit 11 changes its state according to a state (active state/inactivestate) of state setting circuit 10. More specifically, when statesetting circuit 10 is in an active state, address selecting signal ACselecting a location designated by address signal AD as a location towhich data is to be written is output, and when state setting circuit 10is in an inactive state, address selecting signal AC selecting alocation other than the location designated by address signal AD (orselecting neither of the location) is output.

[0092] Based on the address selecting signal AC output from address nonselecting circuit 11, data DT is written into the corresponding locationin data protection region B2.

[0093] Next, an operation of non contact type IC card 500 according tothe fifth embodiment of the present invention will be described.

[0094] First, when state setting circuit 10 is in an active state,address non selecting circuit 11 having received write enable signal REand address signal AD outputs an address selecting signal AC selecting alocation designated by address signal AD. In this case, data DT iswritten into the corresponding location in data protection region B2.

[0095] On the other hand, when state setting circuit 10 is in aninactive state, address non selecting circuit 11 having received writeenable signal RE and address signal AD outputs an address selectingsignal AC selecting a location other than the location designated byaddress signal AD (or selecting neither of the locations). In this case,data DT is not written into the intended location of data protectionregion B2.

[0096] As described above, an example of such state setting circuit 10includes a fuse.

[0097] Thus even if the rewriting operation occurs, non contact type ICcard 500 can inhibit the rewriting of the intended data, after the datarequiring security is stored in data protection region B2 (protectiondata storage state), by controlling the state of state setting circuit10.

[0098] Thus, as non contact type IC card 500 allows the control ofaddress selection in the data protection region at the data writingoperation, rewriting and use of the data previously stored in the dataprotection region can be prevented.

[0099] Sixth Embodiment

[0100] According to the sixth embodiment of the present invention, a noncontact type IC card includes an OTP ROM (an non volatile memoryallowing only one rewriting) as a storage medium corresponding to thedata protection region.

[0101]FIG. 6 shows a structure of a main portion of a non contact typeIC card 600 according to the sixth embodiment of the present invention,wherein components similar to those in non contact type IC card 100shown in FIG. 1 are denoted by the same reference characters and thedescription thereof will not be repeated.

[0102] Non contact type IC card 600 shown in FIG. 6 is different fromconventional non contact type IC card 900 in that it includes a memory15 and a memory 16 instead of memory 1.

[0103] With reference to FIG. 6, the structure of non contact type ICcard 600 according to the sixth embodiment of the present invention willbe described.

[0104] Memory 15 is a storage medium storing rewritable data whereasmemory 16 is a storage medium storing data requiring the security.

[0105] Specifically, memory 15 includes a non volatile memory allowingrewriting as required such as an EEPROM and a flash memory, whereasmemory 16 includes a memory allowing only one rewriting such as anEPROM.

[0106] Next, an operation of non contact type IC card 600 according tothe sixth embodiment of the present invention will be described. Forsimplicity, in the description, memory 16 is assumed to be an EPROM.

[0107] Data to be held that is output from main control circuit 2 isstored in memory 15 or memory 16.

[0108] In this case, as memory 16 is an EPROM, once electric charge isstored in a memory cell not shown, the electric charge cannot bedischarged until it is exposed to ultraviolet light. Therefore, assumingthat the state of a memory cell with electric charge stored is calledstate 1 and the discharged state of the memory cell is called state 0,after the encapsulation of IC card 600, in memory 16, a memory cell inthe state 0 can be charged to be the state 1, however, a memory cell inthe state 1 cannot be rewritten to be the state 0.

[0109] Therefore, it is highly unlikely that the trial of rewriting ofdata once stored in memory 16 achieves the intended data rewriting.

[0110] Thus, with the use of an OTPROM as a medium for storing data tobe protected, non contact type IC card 600 allows the suppression ofdata falsification to an extremely low level.

[0111] As can be seen from the foregoing, according to the presentinvention, the rewriting of storage region in which data requiring thesecurity is stored can be prevented through the control of datarewriting.

[0112] In addition, according to the present invention, as the rewritingcan be controlled with respect to the storage region in which datarequiring the security is stored, the reliability of the non contacttype IC card can be dramatically improved.

1. A non contact type IC card responsive to externally applied data forperforming data communication, comprising: first storing means (B2)storing said data requiring security; second storing means (B1) storingdata other than said data to be stored in said first storing means (B2);control means (2) controlling for writing said data into a location inone of said first storing means (B2) and said second storing means (B1)according to a content of said data; selection means (4) selectingwhether said data is to be written into said location in said firststoring means (B2) designated by said control means (2); and statesetting means (3) controlling the selection by said selection means (4);wherein said data is written into said location in said first storingmeans (B2) designated by said control means (2) when said state settingmeans (3) is in a first state, whereas, said data is inhibited frombeing written into said first storing means (B2) designated by saidcontrol means (2) when said state setting means (3) is in a second stateother than the first state.
 2. A non contact type IC card responsive toexternally applied data for performing data communication, comprising:first storing means (B2) storing said data requiring security; secondstoring means (B1) storing data other than said data to be stored insaid first storing means (B2); control means (12) controlling forwriting said data into a location in one of said first storing means(B2) and said second storing means (B1) according to a content of saiddata; detection means (5) receiving a control signal from said controlmeans (12) and giving instruction for controlling a state of said firststoring means (B2); and selection means (6) receiving the instruction ofsaid detection means (5) and selecting whether said data is to bewritten into said location of said first storing means (B2) designatedby said control means (12); wherein said control signal output from saidcontrol means (12) indicates whether said first storing means (B2) is ina data rewriting permitted state or a data rewriting inhibited state,and said data is written into said location in said first storing means(B2) designated by said control means (12) when said detection means (5)detects that said first storing means (B2) is in said data rewritingpermitted state, whereas said data is not written into said location insaid first storing means (B2) designated by said control means (12) whensaid detection means (5) detects that said first storing means (B2) isin said data rewriting inhibited state.
 3. A non contact type IC cardperforming a data communication based on an externally applied radiowave signal, comprising: receiving means (20) receiving said radio wavesignal; first storing means (B2) storing said data requiring security;second storing means (B1) storing data other than said data to be storedin said first storing means (B2); control means (2) generating said databased on the radio wave signal received at said receiving means (20) andcontrolling for writing said data into a location in one of said firststoring means (B2) and said second storing means (B1) according to acontent of said generated data; detection means (7) detecting afrequency of the radio wave signal received by said receiving means(20); and selection means (8) selecting whether said data is to bewritten into said location in said first storing means (B2) designatedby said control means (2) based on a result of the detection by saiddetection means (7); wherein when said receiving means (20) receivessaid radio wave signal and the frequency of said radio wave signal isdetected to be a first frequency by said detection means (7), said datais written into said location in said first storing means (B2)designated by said control means (2), whereas when the frequency of saidradio wave signal is detected to be a second frequency other than saidfirst frequency by said detection means (7), said data is not writteninto said location in said first storing means (B2) designated by saidcontrol means (2).
 4. A non contact type IC card responsive toexternally applied data for performing data communication, comprising:first storing means (B2) storing said data requiring security; secondstoring means (B1) storing data other than said data to be stored insaid first storing means (B2); control means (2) controlling for writingsaid data into a location in one of said first storing means (B2) andsaid second storing means (B1) according to a content of said data; anddata fixing means (9) receiving said data to be written into saidlocation in said first storing means (B2) designated by said controlmeans (2) and supplying a particular data; wherein only said particulardata supplied from said data fixing means (9) is written into saidlocation in said first storing means (B2) designated by said controlmeans (2).
 5. The non contact type IC card according to claim 4, whereina value of said particular data supplied from said data fixing means (9)is a value determined by an initial state of said first storing means(B2).
 6. A non contact type IC card responsive to externally applieddata for performing data communication, comprising: first storing means(B2) storing said data requiring security; second storing means (B1)storing data other than said data to be stored in said first storingmeans (B2); control means (2) controlling for writing said data into alocation in one of said first storing means (B2) and said second storingmeans (B1) according to a content of said data; selection means (11)selecting whether said data is to be written into said location in saidfirst storing means (B2) designated by said control means (2); and statesetting means (10) controlling the selection by said selection means(4); wherein said data is written into said location in said firststoring means (B2) designated by said control means (2) when said statesetting means (10) is in a first state, whereas, said data is writteninto a location other than said location in said first storing means(B2) designated by said control means (2) when said state setting means(10) is in a second state other than the first state.
 7. The non contacttype IC card according to claim 1, wherein said state setting means (3,10) includes a fuse, said fuse is in an electrically conductive state insaid first state and said fuse is in an electrically non conductivestate in said second state.
 8. The non contact type IC card according toclaim 6, wherein said state setting means (3, 10) includes a fuse, saidfuse is in an electrically conductive state in said first state and saidfuse is in an electrically non conductive state in said second state. 9.Anon contact type IC card responsive to externally applied data forperforming data communication, comprising: first storing means (16)storing said data requiring security; second storing means (15) storingdata other than said data to be stored in said first storing means (16);control means (2) controlling for writing said data into a location inone of said first storing means (16) and said second storing means (15)according to a content of said data; wherein said first storing means(16) allows rewriting of a predetermined times.
 10. The non contact typeIC card according to claim 9, wherein said first storing means (16)includes an EPROM.
 11. The non contact type IC card according to claim9, wherein said second storing means (15) includes an EEPROM.
 12. Thenon contact type IC card according to claim 9, wherein said secondstoring means (15) includes a flash memory.